Risk factors for parathyroid cancer

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes parathyroid cancer develops in people who don’t have any of the risk factors described below.

Parathyroid cancer is very rare. Most people diagnosed with this disease are middle aged. It affects men and women equally.

Some people can have a higher than average risk for parathyroid cancer. Talk to your doctor about your risk. If you are at higher than average risk, you may need a personal plan for testing.

Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.

Known risk factors

There is convincing evidence that the following factors increase your risk for parathyroid cancer. All of these known risk factors are not modifiable. This means that you can’t avoid them. Until we learn more about these risk factors, there are no specific ways you can reduce your risk of parathyroid cancer.

Multiple endocrine neoplasia

Multiple endocrine neoplasia (MEN) is a group of rare hereditary conditions that cause tumours in the endocrine glands. The tumours are usually non-cancerous (benign), but in rare cases they are cancerous (malignant).

There are different types of MEN, which are each caused by changes (mutations) in different genes. Each type of MEN affects certain endocrine glands. MEN1 is the type that most often causes tumours in the parathyroid glands. MEN2A may also cause parathyroid tumours. People with MEN1 are more likely to develop parathyroid cancer than people with MEN2A.

Hyperparathyroidism-jaw tumour syndrome

Hyperparathyroidism-jaw tumour (HPT-JT) syndrome is a hereditary condition caused by a mutation in the CDC73 gene. HPT-JT causes tumours to develop in the parathyroid gland. These tumours cause one or more of the parathyroid glands to become overactive and make too much parathyroid hormone (called hyperparathyroidism). The tumours are usually non-cancerous parathyroid adenomas. About 15% of people with HPT-JT syndrome develop parathyroid cancer. People with HPT-JT syndrome may also develop a type of non-cancerous tumour (called a fibroma) in the jaw bone.

Familial isolated hyperparathyroidism

Familial isolated hyperparathyroidism (FIHP) is a hereditary condition that causes one or more of the parathyroid glands to become overactive. It can be caused by changes in the MEN1, CDC73, CASR or CDKN1B gene. FIHP is usually diagnosed when there are no symptoms or features of other conditions, such as MEN or HPT-JT. Most people with FIHP have non-cancerous parathyroid tumours that cause the glands to be overactive. In rare cases, people with FIHP develop parathyroid cancer.

Possible risk factors

The following factors have been linked with parathyroid cancer, but there is not enough evidence to show they are known risk factors. More research is needed to clarify the role of these factors for parathyroid cancer.

Radiation to the head and neck

People who received radiation therapy to the head and neck have a higher risk for developing parathyroid tumours. This risk factor is more commonly linked with developing non-cancerous parathyroid tumours. But some people who have radiation to the head and neck may develop parathyroid cancer.

Certain gene mutations

Many gene mutations are linked to parathyroid cancer, including mutations in the retinoblastoma gene, p53 gene and BRCA2 gene. These mutations can be inherited, or they can happen during a person’s lifetime (called sporadic mutations).